"Very well done and exciting. Congratulations."
In the two decades that have passed since Morton and colleagues1 introduced their landmark technique for the identification of sentinel lymph node (SN) metastasis in patients with malignant melanoma, sentinel lymph node biopsy (SLNB) has proved to be a remarkable tool in the treatment of solid cancers and has dramatically changed the manner in which regional nodal disease is managed.
The SN concept is that lymphatic flow away from a primary tumor drains through one, or sometimes several, first or SNs as it enters the regional nodal basin. By definition, these nodes receive their drainage directly from the tumor and not from any other nodes. Cancer spread through the lymphatics should first be deposited in the SN and detailed examination of that node should accurately predict the status of the remaining nodal basin. This not only identifies those patients who are most likely to benefit from a completion nodal dissection (CLND), but also results in more accurate pathological staging.
Although SLNB was originally introduced in the management of malignant melanoma, the technique was also rapidly and successfully applied to invasive breast cancer.2 Since then, clinicians have investigated the applicability of SLNB to an ever-increasing number of malignancies, including thyroid cancer, lung cancer, multiple gastrointestinal malignancies, and even head and neck cancer.3–6 The ultimate role of the SN technique is yet to be determined for many of these different malignancies, and refinements to both technique and indication are frequently proposed as worldwide experience increases. This article will focus principally on the current role of SLNB in the management of malignant melanoma, invasive breast cancer, and colon cancer—the three malignancies with the greatest amount of collective data available upon which recommendations can be based. Specific details for the SN technique in treating these cancers and others are sufficiently described elsewhere and will not be emphasized to any great extent here.